1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel with reduced flicker and more particularly to a compensation circuit for enabling scanning lines or data lines of the liquid crystal display panel to have the same time constants.
2. Description of the Related Art
A conventional liquid crystal display panel comprises an active matrix substrate 10, as shown in FIG. 1. The active matrix substrate 10 has a plurality of data lines 13 and a plurality of scanning lines 12; the data lines 13 and the scanning lines 12 cross each other to form a plurality of pixels arranged in a matrix. In addition, a plurality of thin film transistors (TFTs) are formed within an active area B, which is the area where the data lines 13 and the scanning lines 12 cross perpendicularly.
There are a plurality of outer-lead bonding (OLB) areas 14 surrounding the active area B. A plurality of pads are formed within the outer-lead bonding areas 14, so that driving devices can be connected to the outer-lead bonding areas 14. And a fan-out area 16 arranged a plurality of wires 15 is disposed next to the inner side of each outer-lead bonding area 14.
FIG. 2 is a magnified schematic view of the portion C in FIG. 1. Each wire 15 extends from the outer-lead bonding area 14 so as to be connected, along a straight line, to a scanning line 13 of the active area B.
Since the length of the outermost wire 151 is far different from that of the central wire 152, it is understood that a maximum resistance and a minimum resistance are found in the outermost wire 151 and the central wire 152, respectively. That may be the resistance of the wire 15 calculated as follows:
      R    =          ρ      ⁢              L        S              ,where ρ, L and S respectively represent resistance, length, and cross sectional area of the wire 15.
The product of resistance R and capacitance C is directly related to the delay time of a signal transmitted by either one of the data lines 13 or one of the scanning lines 12. So, the wires 15 have different RC time constants between them whenever driving signals are sent from the driving devices connected to the outer-lead bonding areas 14; as a result, the driving signals are subjected to varying degrees of delay effect when carried by the wires 15.
A primary cause of the flickers that occur in liquid crystal display panels is the above-mentioned delay effect. On one hand, delay time constants vary from one scanning line 12 to another scanning line 12 and thus flicker points are visible if watched specially along the vertical direction; on the other hand, relatively great delay effect is accumulated at the end of the same scanning line 12 opposite to the respective driving device, thus scanning signals are distorted when they reach the distal end of the scanning line 12 and, in consequence, the corresponding pixels fails to display a current gray level changed from a previous gray level within the right period as scheduled, resulting in flicker points visible to an individual watching along the horizontal direction.
In short, there is great demand for a liquid crystal display panel free from flickers and therefore conducive to quality display.